Google Chrome has a feature to change between Google accounts which allows several users to have their customized extensions, history and whatnot retrieved instantly. It doesn't, however, protect someone else from checking anything google related. That means anyone with access to your computer can check every google account that was setup as user in Chrome.

How can I prevent that? I first thought of checking a box with the option to have Chrome request for password upon user change but that doesn't seem to exist.

The ability to add multiple users to Chrome is intended to provide a quick and simple way to set up personalized copies of Chrome for people who are already sharing Chrome on the same computer today. It isn’t intended to secure your data against other people using your computer. To truly protect your data from being seen by others, please use the built-in user accounts in your operating system of choice.

It’s also helpful to think of the profiles as different setups for the same person. For example, you may have a couple of aliases, or have a work profile and personal one, etc. In that case, security from other people isn’t even expected.
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SynetechJun 10 '12 at 16:01

Damnit. It would make my life so much easier. =/
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RenanJun 10 '12 at 16:59